The present disclosure relates to an induction heating unit, and a fixing device and an image forming apparatus including this.
An image forming apparatus, such as a copying machine, facsimile and printer, includes an image forming part forming an image on an image carrier (e.g. a photosensitive drum), a transferring part transferring a toner image on the image carrier onto a sheet as one example of a recording medium and a fixing device heating the toner image transferred on the sheet and fixing it onto the sheet.
As the fixing device, that including an electromagnetic induction heating (IH) unit making rapid heating and high efficient heating possible is known. In such an electromagnetic induction heating manner, induced current is induced to a fixing roller or a fixing belt by magnetic flux generated by flowing high frequency current to an induction coil, and then, Joule heat (induction heat) is generated in the fixing roller or the fixing belt. By the Joule heat, the toner image is fixed onto the sheet (the recording medium).
For example, in the fixing device including the electromagnetic induction heating unit, a technique holding an arch core making a magnetic path by a given holder is proposed. Between the arch core and the holder, an elastic member is arranged. When a shield in a lid shape is attached to the holder, the arch core is positioned by elastic force of the elastic member.
In the above-mentioned fixing device, there are problems that, when the shield is attached to the holder, a position of the elastic member is shifted and the position of the arch core is not accurately determined.